Field of Invention
This application generally relates to minimally invasive surgery and to virtual reality systems.
Description of Related Art
Since its inception in the early 1990s, the field of minimally invasive surgery has grown rapidly. While minimally invasive surgery vastly improves patient outcome, this improvement comes at a cost to the surgeon's ability to operate with precision and ease. During laparoscopy, the surgeon must insert laparoscopic instruments through a small incision in the patient's abdominal wall. The nature of tool insertion through the abdominal wall constrains the motion of laparoscopic instruments as laparoscopic instruments cannot move side-to-side without injury to the abdominal wall. Standard laparoscopic instruments are limited to four axes of motion. These four axes of motion are movement of the instrument in and out of the trocar (axis 1), rotation of the instrument within the trocar (axis 2), and angular movement of the trocar in two planes while maintaining the pivot point of the trocar's entry into the abdominal cavity (axes 3 and 4). For over two decades, the majority of minimally invasive surgery has been performed with only these four degrees of motion.
Existing robotic surgical devices attempted to solve many of these problems. Some existing robotic surgical devices replicate non-robotic laparoscopic surgery with additional degrees of freedom at the end of the instrument. However, even with many costly changes to the surgical procedure, existing robotic surgical devices have failed to provide improved patient outcome in the majority of procedures for which they are used. Additionally, existing robotic devices create increased separation between the surgeon and surgical end-effectors. This increased separation causes injuries resulting from the surgeon's misunderstanding of the motion and the force applied by the robotic device. Because the degrees of freedom of many existing robotic devices are unfamiliar to a human operator, surgeons must train extensively on robotic simulators before operating on a patient in order to minimize the likelihood of causing inadvertent injury.
To control existing robotic devices, a surgeon sits at a console and controls manipulators with his or her hands and feet. Additionally, robot cameras remain in a semi-fixed location, and are moved by a combined foot and hand motion from the surgeon. These semi-fixed cameras with limited fields of view result in difficulty visualizing the operating field.
Other robotic devices have two robotic manipulators inserted through a single incision. These devices reduce the number of incisions required to a single incision, often in the umbilicus. However, existing single-incision robotic devices have significant shortcomings stemming from their actuator design. Existing single-incision robotic devices include servomotors, encoders, gearboxes, and all other actuation devices within the in vivo robot. This decision to include the motors and gearboxes within the patient's body has resulted in large robots with limited capability. Such a large robot must be inserted through a large incision, thus increasing risk of herniation, risk of infection, pain, and general morbidity. The incision size required for some existing devices is between 1.5 and 2 inches—an incision size similar to open surgery. Additionally, it is unlikely that the size of these devices will ever significantly decrease due to the inclusion of motors, gears, etc. within the in vivo devices. This increased incision size results in significantly increased injury to the patient and vastly reduces the practicality of existing devices.
Existing single incision devices also have limited degrees of freedom. Some of these degrees of freedom are non-intuitive to a human, for example elongation of the arm during a procedure. These degrees of freedom require a user interface where the surgeon must make non-intuitive learned movements similar the movements existing multi-incision devices.
Human-Like Robotics
A few people have previously suggested the idea of surgical robotics designed to replicate the degrees of freedom of a human arm. However, all existing designs include extraordinarily complex gearboxes and gear trains all placed within the robotic arms. As a result of these gearboxes and gear trains, existing human-like arms are both difficult to manufacture, large in size, and low in speed. In addition, no previous inventors of human-like robotics describe human-machine interfaces designed to fully utilize the advantages of human-like robotics. Without a proper human-machine interface, a human like arm provides little or no advantage over alternative robotic designs.